Dishwashers of various types have been proposed wherein items are placed in a wash chamber which is filled and emptied according to desired wash sequences. Recently, dishwasher manufacturers have focused even more on efficiency in implementing new designs. Thus, an amount of electricity, an amount of detergent, and an amount of water used are all monitored or otherwise attempted to be reduced in an attempt to provide efficient and environmentally sensitive machines.
Many dishwashers have more than one outlet within them for spraying water within the wash chamber. For example, dishwashers typically have an upper rack and a lower dish rack. Such dishwashers may have a multiple rotating spray arms located at a lower level, a midlevel (between dish racks), and an upper level that spray during a wash or rinse cycle. Some dishwashers have two such sprayers and some have more.
To reduce the amount of water used in such multiple sprayer dishwashers, it can be desirable to alternate spraying between the multiple spray arm assemblies. Doing so requires a smaller amount of water in the wash chamber because only half of the spray system need be actively filled with water at a time.
One way in which such alternate spraying schemes are achieved is through the use of a diverter valve. For example, the diverter valve can be a valve device that can be placed into multiple positions or configurations. Each position can direct the flow of water according to a different pattern or destination(s). Therefore, by controlling or otherwise operating the diverter valve, the dishwasher can switch between various spray schemes or other desired water flow patterns.
Thus, knowledge of the current position of the diverter valve and the ability to place the diverter valve into a desired position is typically required for proper diverter valve operation and control. For example, certain control variables may be stored in a non-volatile memory and used by a microprocessor control device when controlling the diverter valve.
However, over time, wear and tear on a system can alter the operating parameters or part performance of the diverter valve. As examples, a motor that rotates the diverter valve between positions may become less effective over time, rotating diverter parts may suffer from increased friction over time as lubricants are lost or parts become worn, or replacement parts may be introduced into the diverter valve assembly or associated components. When such operating parameters are altered, use of pre-set control variables can impair the ability of the dishwasher to successfully place the diverter valve into a desired position.
Therefore, diverter valves and associated dishwashers that provide continuous calibration over the lifespan of the diverter valve are desirable.